Yoshigadaira Wetlands

Overview of Yoshigadaira moor
Yoshigadaira moor ponds
Eriopqhorum vaginatum in Yoshigadaira
Odaira moor pond
Odaira moor pond
Asian skunk cabbage (Lysichiton camtschatcense)
Heibeeike pond
Oike pond
Mizu-ike pond
Mt. Kusatsu-Shirane
Yugama crator lake
Solfatara plants
Anajigoku Overview
Anajigoku (Jungermannia volcanicola communities)
Anajigoku (Jungermannia volcanicola communities)
Forest Green Tree Frogs at Heibee pond

Yoshigadaira Wetlands

  • Country: 
  • Site number: 
  • Area: 
    887 ha
  • Designation date: 
  • Coordinates: 
    36°38'N 138°34'E
Materials presented on this website, particularly maps and territorial information, are as-is and as-available based on available data and do not imply the expression of any opinion whatsoever on the part of the Secretariat of the Ramsar Convention concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.


Yoshigadaira Wetlands are located in the centre of Honshu Island on the north-east flank of Mount Kusatsu-Shirane, an active volcano that erupted eight times in the 30 years to 2015. The Site comprises a group of moors, ponds, a lake and a stream which developed on low-permeable layers, depressions and a crater created by the volcanic activities. The Site is unique because of the high temperature and acidity from the volcano and volcanic gases such as hydrogen sulphide. The water of the Anajigoku stream is extremely acidic (pH 2.6-2.8) with abundant iron and sulphur, but it hosts the largest community of the aquatic liverwort Jungermannia vulcanicola in East Asia. The water of Yugama, a crater lake near the top of Mt. Kusatsu-Shirane, is even more acidic (pH 1.0-1.2) and so there is little vegetation in the area. Yoshigadaira moor and Odaira moor provide an important refuge in the surrounding volcanic area for animal and plant species that depend on the wet environment. The geothermal heat and water around the Yoshigadaira Wetlands enable wild fauna and flora to survive the winter at altitudes up to and beyond 2,000 metres and temperatures below -15°C. For example, the breeding site of the forest green tree frog Rhacophorus arboreus in Yoshigadaira Wetlands is at 2,150m, the highest recorded in the world.

Administrative region: 
Nakanojo town, Agatsuma-gun, Gunma Prefecture

  • Global international designation: 
    • UNESCO Biosphere Reserve
  • National legal designation: 
    • National Park - Joshin’etsukogen National Park
  • Last publication date: 


Ramsar Information Sheet (RIS)